First off, I love Perl, but I hate it too. All of my backend code used to be Perl, but I long since abandoned it for Ruby. Now when I have to use Perl, it's usually called from a Ruby script and I real the Perl output into Ruby through JSON.
As far as performance is concerned, i think Python is really a top contender with native thread support, but generally for sysadmin stuff, you don't always need a high-performance solution. For something that is easy-to-write, and easy-to-manage, and almost more importantly easy-to-read-the-code-2-months-later, Ruby is great. I have nothing bad to say about Perl, but there are clearly some advantages (when using objects especially) to Ruby and Python. The Perl community (perlmonks.org) is the best programming community I've ever come across. The only reason I even switched to Ruby was because I believed that Parrot would bring a convergence and interoperabilty between Perl 6, Ruby and Python.
If Perl becomes less relevant in the future it would make me sad.